AIP-3: Upgrade Aave V1 LendingPool contract for seamless migration to V2

At the time of writing, 11341692 aLEND are deposited in the Aave protocol reserve lendingPoolCorecontract, several community members currently use these assets as collateral in loans and would like to migrate both from LEND to AAVE and from V1 to V2 in the future.

Outside of the situation of the aLEND holders, having a Flashloan-powered migration tool used for every asset available on V1 to allow seamless migration from v1 to v2 would significantly ease the process of upgrading the liquidity to the new version of AAVE.

A third benefit will be an increased volume of Flashloans and a good use case of the capabilities of the Aave V2 new flashloans.

To allow these new features, small modifications of the repay() method are needed to upgrade the efficiency of the process and allow v2 flashloans to access it.

Please find the AIP-3 here

After discussions with the community the AIP-3 will be submitted to vote to the AAVE tokens holders and directly integrated if the vote outcome is in favour of a approval.